Pardon me, then. I was under the delusion that ash was
actually a useful shell, rather than being a glorified POSIX
validation suite.
I'll deprecate ash as a shell, in that case, and look for a
real shell to use as a /bin/sh (bash makes me uneasy).
Do we have a non-toy shell to use as /bin/sh replacement then?

pdksh is what OpenBSD uses as /bin/sh. The binary is slightly larger
than ash, and the RSS is about 100k larger.